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Presentation on theme: "Natural Hazards and Risks: so far what do you know?"— Presentation transcript:

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Natural Hazard versus Population Population Where there is an interaction between hazard and population, there is the potential for a disaster or higher risk. Where there is an interaction between hazard and population, there is the potential for a disaster or higher risk.

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The Last 10,000 Years of Human History Flat population growth curve until 8,000 years ago –Agriculture established –Domestication of animals –Growth rate increased to 0.036%/year By 2,000 years ago, population ~200 million people –Better shelter, food, water supplies  faster population growth –Growth rate of 0.056%/year By 1750, population ~800 million people Figure 1.8

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The Human Population Today Present population: Almost 7 billion –Growth rate = 1.2%/year –Doubling time = 58 years Growth rate = fertility (birth) rate – mortality (death) rate Human population grows by about 80 million people per year

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Future World Population Demographic transition theory: –Mortality and fertility rates decline from high to low levels because of economic and social development Population Reference Bureau estimates world population growth rates are dropping –From 1.8% in 1990 to 1.2% in 2008 –Due to urbanization and increased opportunities for women

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Urban Growth: change from rural to urban population The world’s urban population is now growing by 80 million persons per year UNPF World trend More developed regions Least developed regions

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Demographic trends trends Developed countries More education a woman receives the less children she will have More education a woman receives the less children she will have Higher life expectancy Higher life expectancy Developing countries Higher birthrates Higher birthrates Larger % of pop., young Larger % of pop., young Lower life expectancy Lower life expectancy Become refugees due to political unrest Become refugees due to political unrest 1 in 7 people in the world live in slum conditions 1 in 7 people in the world live in slum conditions

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Lack resources Lack resources shelters are poorly constructed and population is concentrated. shelters are poorly constructed and population is concentrated. People often inhabit floodplain, hillsides and other “leftover” areas. Problem?

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Haiti 2 million people in Port au Prince 2 million people in Port au Prince Infrastructure for 100,000Infrastructure for 100,000 Housing: lack of reinforcement Housing: lack of reinforcement 75% of population live on less than $2/day 75% of population live on less than $2/day

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Chile Building codes similar to the United States Largest earthquake ever recorded in 1960 Largest earthquake ever recorded in 1960 Magnitude 9.5 Magnitude 9.5 Magnitude 7.1, January 3, 2011 Magnitude 7.1, January 3, 2011 Recovery continues Recovery continues About 30% of the population lives in poverty

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ECONOMIC STANDING: VERY IMPORTANT FACTOR REGARDING RISK AND RECOVERY

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Deaths due to natural disasters Most mega-killer disasters occur in densely populated belt through Asia, along Indian Ocean – number of fatalities is proportional to density of population Most mega-killer disasters occur in densely populated belt through Asia, along Indian Ocean – number of fatalities is proportional to density of population

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The number of disasters through time has increased The number of disasters through time has increased Why? Why? More hazards?More hazards? More people in the way of hazards?More people in the way of hazards?

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Disaster Frequency and Magnitude The greater the magnitude, the rarer the event The greater the magnitude, the rarer the event How many people understood the potential hazard from a tsunami before 2004? How many people understood the potential hazard from a tsunami before 2004? Haiti earthquake? Haiti earthquake? Low High Magnitude Common Rare

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Disaster Magnitude and Return Period The greater the magnitude, the longer the return period The greater the magnitude, the longer the return period When was the last time a large earthquake occurred in California? When was the last time a large earthquake occurred in California? Low High Magnitude Long Brief

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Economic Loss Includes destruction of: Includes destruction of: Buildings and roads Buildings and roads Water and electricity Water and electricity Businesses and industries Businesses and industries Employment Employment Takes years to determine Takes years to determine

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Insured losses Developed countries have: Developed countries have: higher insured losses higher insured losses Lower number of fatalitiesLower number of fatalities Developing countries have: Developing countries have: lower insured losses Higher number of fatalities Increase in economic losses over time is result of increase in human population and urbanization

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How many people can Earth support? –Calculations of carrying capacity vary considerably –Increasing amounts of food can be produced –People can migrate from areas of famine or poverty to less crowded or wealthier areas Figure 1.15 Carrying Capacity –BUT Earth’s resources are finite, so solutions are temporary

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Carrying Capacity Example of Rapa Nui (Easter Island) –Isolated Pacific island with poor soil and little water –Settled by 25-50 Polynesians in 5 th century Figure 1.14 Survived easily on chickens and yams, plenty of free time Developed elaborate competition between clans with moai (statues) –Civilization peaked at 1550, with population of ~7000

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Example of Rapa Nui (Easter Island) –Reached by a Dutch ship in 1722 Found about 2,000 people living in caves Primitive society, constant warfare –Rapa Nui’s carrying capacity had been drastically lowered by society’s actions: Transportation of moai had required cutting down trees Erosion of soil made yams scarce Lack of canoes made fishing difficult and escape impossible Carrying Capacity

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Larger events are less common Larger events are less common Increase cost due to increase economic loss Increase cost due to increase economic loss Increase of population Increase of population Change from rural to urbanChange from rural to urban Structures and population concentration without consideration of hazardsStructures and population concentration without consideration of hazards Carrying capacity: the ability for the population to live and thriveCarrying capacity: the ability for the population to live and thrive Bottom Line?